1. Field
The present invention relates generally to integrated reference sources and, more particularly, to target designator systems for high-precision guidance of guided munitions.
In this disclosure, the polarized Radio Frequency (RF) reference sources and geometrical cavities as described in U. S. Pat. 6,724,341 and 7,193,556; U.S. patent application Publication 2007/0001051, now U.S. Pat. No. 7,425,998, hereinafter referred to as “polarized RF position and angular orientation sensors” and preferably “scanning polarized RF reference sources” as described in the U.S. Ser. No. 11/888,797, filed Aug. 2, 2007 and Ser. No. 12/191,295, filed Aug. 13, 2008, hereinafter referred to as “RF reference sources,” all of which are incorporated herein by reference, are used to form an integrated target designation and reference source system for high precision guidance of guided munitions towards its target.
2. Prior Art
In general, a human or machine (such as an “Unmanned Aerial Vehicle” or UAV, or an “Unmanned Ground Vehicle” or UGV or a manned aerial or ground vehicle, or the like) is used to identify the target. Some means (e.g., one or more of the systems and devices such as “Global Positioning System” GPS, range finders, inertial devices, etc.) are then used to determine the position of the target and other relevant target indication information. Hereinafter, the above human or machine that is used to determine the position of the target is referred to generally as the “forward observer”.
In general, the position of the target is determined by the “forward observer” and is indicated relative to the earth. The “forward observer” must also determine its own position relative to the earth. The weapon platform that is to engage the target must also know its own position relative to the earth. The target position and other information that is acquired by the “forward observer” is then passed to the engaging weapon platform fire controller (usually a computer), which would then perform proper computations and pass target position and other guidance and control information to the guided munitions that is to be launched against the designated target. Once launched, the guided munitions will use the target position information (and sometimes target position updates when it is available) to guide itself to the designated target position. Near the target, guided munitions may, when equipped with some type of homing sensors, also use such sensors to guide them to the target.
As indicated above, in most current munitions guidance and control systems, the position of the target is determined by the forward observer relative to the earth, i.e., the earth is considered to be the reference system in which the position of the target, the weapon platform, and the forward observer is defined. In addition, the guided munitions, such as projectiles fired from a gun or a mortar, monitors its position relative to the same earth based (fixed) position reference system. There is, however, an error in each one of the above four position measurement relative to the aforementioned earth fixed reference system. As a result, the four position measurement errors add up to make up the amount of positioning error that the guided munitions can have relative to the target that it is desired to intercept, leading to a significant degradation of the precision with which a target could be intercepted.
In general, the only means available for increasing the precision with which guided munitions can be guided to intercept a desired target is the provision of some type of homing device. Such homing systems may, for example, include target seekers such as heat seeking sensors or various guidance systems utilizing laser designators, etc. Such homing systems usually require sophisticated sensory devices that occupy relatively large spaces onboard and require relatively high onboard power to operate, which make them not suitable for many munitions applications, particularly gun-fired munitions (particularly small and medium caliber munitions) and mortars. In addition, homing systems using various target designators such as laser target designators generally requires a forward target observer, usually a human, to designate the target, which is also generally not a desirable solution.